Justop G-PC Quad Core Windows 8.1 Mini PC (1 Viewer)

HTPCSourcer

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    Here is my user report and setup description of the Justop G-PC Quad Core Windows 8.1 Mini PC, which I bought from Amazon UK for 90 GBP (ca. 125 EUR):

    Justop PC.jpg

    The PC comes in a small carton, together with the PSU and a 1m long HMDI cable.

    A few things should be considered when installing in a non-UK environment:
    • Power Supply
      • First surprise: the PSU is a 12V/2.5 A unit that comes with fixed electric UK connector
      • International users will either have to use a UK->EU adapter (ca. 2.50 EUR on Ebay) or buy a new supply at additional cost
    • Power consumption
      • 0.3W when completely off
      • 4.5W Windows desktop, inactive
      • 8.0W TITANIUS home menu screen
      • 7.1W MePo fullscreen TV 720p source
      • 9.0W MePo fullscreen TV 1080i source
      • 2.2W standby with "modified" energy options (see discussion about USB)
    • BIOS
      • Pressing DEL during startup gets you into a pretty complex BIOS
      • Initial settings are quite good and very little further tweaking is required
      • Power management
        • I activated the only disabled function (use all C-states)
        • There is no visible option for WOL (see discussion about LAN chip)
        • There are two choices for action after power failure: resume (S0 state) or stay off (S5 state). Because of missing WOL I choose the first option.
        • All other options were left unchanged.
    • Installation
      • 1. At the first launch the PC is booting into an En-US Windows 8.1
        • There is one user account "Mini" (Administrator) without a password set
        • Unless you want to have "Mini" as your name showing in network environment, etc. you should now create a new user account for your MediaPortal activities with the desired name. If you set this up as administrator you can delete the old user account Mini or keep it as the admin account.
      • 2. Net 3.5
        • As you know .NET 3.5 is required by the MePo installer to run (not by the MePo software itself).
        • Activate .Net 3.5 in the Windows features before changing Region and Language information and connecting the PC to a WSUS update system, that you might have running
          • The Windows system is an English-US one and some system data and messages will always be in English, even after having applied a language package.
          • When activating .Net 3.5 the Windows Update is searching for drivers in the original Windows language (English), which it is not finding on a localized system. It then tries to contact the Microsoft update servers. With WSUS in place chances are big that the installation will fail.
          • After this initial step download from Microsoft, further .Net 3.5 security updates will install without issues from the localized WSUS
      • 3. Set up your localization under Region and Language per your requirements
      • 4. Windows updates
        • Run Windows update until all important updates are installed. Be patient - especially KB 2919355 takes more than an hour. As there is no HD indicator, you could get the impression that the update process got stuck.
        • Updates for the in-built Bluetooth adapter and the Realtek WLAN chip are available. These are quite new (2015), hence you may want to install them.
    • System setup
      • Windows
        • Deactivate lock screen to allow immediate boot into the desktop
          • Create a new registry key Personalization in HKLM/Software/Policies/Microsoft/Windows
          • Create a DWORD entry NoLockScreen and set its value to 1
        • Automatic logon
          • Press Win-R and enter netplwiz
          • Deactivate "User must enter a password"
          • Click "Apply", select the account that you want to use, enter the password (twice) and close with OK
        • Reboot to test if Windows is now booting into the desktop
        • Clean up already installed software and delete the pre-installed Microsoft Office
    • Standby and Wake-up
      • The system will correctly enter S3 according to the Windows energy profile that you have defined
      • Unfortunately all attempts to wake the system up with mouse, keyboard or remote fail. You have to press the button on the PC
        • Reason: the original settings shut off all USB hubs when in standby. The LAN adapter is a "DM9621A USB To FastEthernet Adapter", no surprise that no WOL is possible.
        • Solution: open the device manager and search for the Generic USB Hub entry. Open its properties and deselect the energy option "Allow the computer to turn off this device to save power".
          • This way the connected USB devices remain on.
          • The PC can now be resumed from sleep with the MCE remote
          • This comes at the price of increased power consumption of 2.2W in S3.
          • Note that WOL from S5 will never be possible
    • WOL
      • Magic packets will not wake up the PC!
      • I tried all different possibilities, i.e. keeping all USB controllers active, yet without success
    The complete installation leaves approx. 10-12 GB of the 32 GB Flash ROM available for other usage
     

    HTPCSourcer

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    MediaPortal installation and practical test - Thermal design

    MediaPortal 1.12 installs smoothly on the system. Use LAV codecs instead of Microsoft-DTV as the latter is not running well on the Justop.
    Video replay and TV work as expected, both for 720p/1080p as well as the more demanding 1080i sources. 4k will not play.

    However, after some time of playing I realized that the picture was becoming choppy, particularly on 1080i, which suddenly was playing at 30 fps only instead of the expected 50 fps.

    1080i.jpg

    After some search and hints from the forum, the reason turned out to be related to the bad thermal design of the Justop. In fact CPU/GPU is quickly heating up and the CPU speed is throttled down to a constant 500 MHz in the case of 1080i.

    Taking the case apart reveals the little hardware inside:

    Justop.jpg

    It can be seen that the system is really completely passive - there is not even a visible heatsink. Actually the system is using the bottom of the case as heatsink, which when playing video is getting really hot. The thermal design of the system is not well thought-out:
    • There are venting openings at the bottom of the case, but it comes without spacers. When used the openings will be blocked.
    • There are no venting openings on the top of the case.
    • The removable top part of the case, which is painted black, has practically no thermal connection with the bottom. While the latter gets hot, the top stays cold.
    In order to test the cooling hypothesis I took the heatsink of an old graphics card that was still lying around and just placed it on the bottom of the Justop (case upside down). No thermal paste or anything applied.

    Heatsink.jpg

    Then I put a 720p TV station on, which presents little load for the GPU. The heatsink immediately started to get warm. After 45 min the fps was still at 50.
    After that I switched to a 1080i station. The fps quickly dropped to 30-40 fps, but pressing the heatsink to the surface of the case brought it back to 50 fps.

    This lets me believe that a correct mounting of the heatsínk by using heatsink glue will solve the issue without having to completely unmount and rebuild the device. Screwing the heatsink to the case would obviously be better, but drilling holes into it with the electronics still in it, is probably not a good idea. I am also thinking of adding a small heatsink on the big metal cover on the board (see picture of the open case) and also drill a series of venting holes into the top of the case cover. There would even be enough space left inside the case to add a small fan.

    I will update this thread once I have found a permanent solution
     
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    dcweather

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    Thanks, most useful and easy to do if required.
    P.S
    I've got a defunct laptop with one of those copper pads and bars that leads from the processor to a small heatsink by slots in the side. I might be able to mod that to take heat from the bottom to the top and out through holes.
    Dave
     

    RonD

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    Your results are similar to what I saw earlier on my HP Stream8 tablet with a Z3735G SOC (System On Chip) processor win8.1. I was using MP1, v1.9 with LAV for testing. Also tried VLC both VLC-desktop and VLC-StoreApp. For all tests I copied the 720P/1080i to local "disk" to get Wifi out of the path, all tests full-screen. Link to my earlier message https://forum.team-mediaportal.com/threads/intel-compute-stick.129271/#post-1120626

    Bottom line using Good = no obvious frame drops/stutter, Bad = obvious frame drops/stutter

    MePo1 rev1.9, 720P = Good, 1080i = Bad
    VLC-desktop, 720P = Good, 1080i = Good
    VLC-StoreApp, 720P = Good, 1080i = Bad

    It is interesting that VLC-desktop works ok for 1080i. Don't know why VLC Desktop works better than Store-App. maybe 2 different ways of starting full screen video?? Wonder what you see with both VLC options on your system.

    My tablet uses Z3735G CPU with only 1 GB DRAM and 32-bit bus and on my tablet I can't change cooling. Your Justop G-PC has 2GB of DRAM so it must be Z3735F or better CPU with 64 bit DRAM bus. So you should have 2X better DRAM performance which should help a bit.
     
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    HTPCSourcer

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    VLC-desktop, 720P = Good, 1080i = Good
    VLC-StoreApp, 720P = Good, 1080i = Bad
    This is interesting and I'll have a look at that. If I am able to confirm this, then we should report this back to the LAV developer because then it might "just" be a software issue. In any case, a VLC codec pack can be downloaded. Maybe better cooling and another codec solves the problem?

    I have ordered a simple cooler (100x160x40 mm;sligthly larger than the Justop case - 100x140), together with adhesive heat-conducting tape. in the meantime I did some research around the 3735 Bay Trail CPU. It looks as if the die is not covered and heat is probably dissipated by means of a conducting plastic pad. The noard is at ~5mm distance from the case. The latter is ~0.7mm steel, which has only 1/10 of the thermal conductivity of copper. All in all there must be some quite significant thermal resistance between CPU die and external cooler. I am really nots ure if things can be arranged without unmounting the board and replacing the plastic heat conductor by a copper plate to reduce thermal resistance.
     

    RonD

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    Another comment I did not think about, Tablet display is 1280x800 not 1920x1080, so both 720P and 1080i are played on 1280x800 with top/bottom bars due to the display pixels/aspect.

    Also did an update for VLC-StoreApp and retested both VLC desktop/store, BOTH now seem to play 720P/1080i cleanly. My earlier tests were in Jan2015 timeframe and VLC SW.
     

    HTPCSourcer

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    Today I received the heatsink (100x160x40 mm) that I had ordered (EUR 12.50). With an advertised heat dissipation of 0.7W/K this is really hard stuff :). It is a little bit larger than the Justop case, but that will be easy to adjust.

    Heatsink.jpg

    Just placing it on top of the case (or rather underneath - it needs to be on the bottom side) resolves the issue! (y) :D:D

    I have now been playing more than 30 min of true 1080i. Of 100000 frames drawn, about 125 were dropped. I believe that once the heatsink wil be correctly glued to the surface, things should be even better.
     

    RonD

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    hmm, looks like the heatsink is bigger than my tablet, what will they say in the coffee shop when I set my heat-sinked tablet down on the table?
     

    HTPCSourcer

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    what will they say in the coffee shop when I set my heat-sinked tablet down on the table?
    Geek?:ROFLMAO:
     

    eetaylog

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    Just so you know, the cpu is definitely not on the bottom of the board as ive lifted the heatpad and theres nothing underneath it. It must be under the metal shielding that i mentioned before, which may make it possible to heatsink to the top lid and avoid having to mount the whole case on a heatsink.

    I will experiment and report back.
     

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